1. Field of the Invention
This invention relates to a magnetic recording medium. More particularly, this invention relates to a magnetic recording medium of outstanding surface property and high electromagnetic property produced by blending a vinyl chloride copolymer solution containing vinyl chloride, a vinyl carboxylate, an unsaturated carboxylic acid and a carboxylic anhydride with a radiation-sensitive curing resin and a magnetic powder, applying the resultant magnetic paint to a non-magnetic substrate, and solidifying the applied layer of paint with radiation.
2. Description of Prior Arts
Magnetic recording media are used extensively in the form of magnetic tapes for audio and video recording, magnetic disks for computers and word processors, and magnetic cards for other household appliances, for example. In the production of such magnetic recording media, the practice of effecting fast adhesion of magnetic powder formulations to their substrates by using a radiation-sensitive curing resin as a binder and cross-linking and polymerizing this binder with radiation is now in vogue.
The magnetic recording media using the aforementioned radiation-sensitive curing resin as the binder, however, have the disadvantage that they have high friction coefficients and are deficient in surface property such as gloss, orienting property and electromagnetic property. As a solution to these disadvantages, we formerly found a resin solution for magnetic paint having as a main component thereof a copolymer of (A) vinyl chloride, (B) a vinyl carboxylate, (C) an unsaturated carboxylic acid and (D) an unsaturated carboxylic anhydride, containing 50 to 80% by weight of (A) based on the total of the amounts of (A) and (B), 60 to 90% by weight of (D) based on the total of the amounts of (C) and (D), and 1 to 5 parts by weight of the total of (C) and (D) based on 100 parts by weight of the total of (A) and (B) and having a average polymerization degree of 100 to 400 (Japanese Patent Open No. SHO 57(1982)-128,711). Magnetic recording media prepared using the solution mentioned above, however, are still unsatisfactory in terms of friction coefficient, gloss, orienting property, electromagnetic property, etc.
An object of this invention, therefore, is to provide an improved magnetic recording medium.
Another object of this invention is to provide a magnetic recording medium which has a low friction coefficient and is excellent in surface property, orienting property and electro-magnetic property.